Adjustable rifle stock



FIG. 1 is an upper left perspective view taken from the front of an adjustable rifle stock showing my new design;

FIG. 2 is a lower right perspective view taken from the front thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a bottom view thereof;

FIG. 7 is a front end elevation view thereof; and,

FIG. 8 is a rear end elevation view thereof.

The broken line showing of portions of the adjustable rifle stock forms no part of the claimed design. 

CLAIM The ornamental design for an adjustable rifle stock, as shown and described. 